Electrodeposition of thiophene-based inherently chiral electrodesurfaces: from traditional media to RTILs

Thiophene-based inherently chiral conducting films, under development in our
research group, have very high and stable chiral activity, depending on a tailored
torsion of the whole conducting backbone rather than on attached chiral pendants;
accordingly, such chirality is modulable by the amount of injected charge (reducing
the torsion angle to achieve better p system conjugation), a phenomenon which
suggested us the image of a breathing system. Perfectly specular electrode surfaces
have been prepared by electrodeposition cycles, starting from the corresponding
inherently chiral oligomers, and their enantiorecognition ability is currently under
study in our group. In order to finely discriminate among the racemate and
enantiomer film properties, and above all to achieve optimized enantiomer electrode
surfaces for applications as chiral sensors, reproducibility is a necessary but hard
task.
In this context, preliminary literature studies [1,2] pointed to room temperature
ionic liquids RTIL, both as such and as cosolvents, significantly improving the
regularity and the mechanical and morphological properties of the conducting films to
be employed e.g. in the energetic, optoelectronic, and sensoristic domains (besides
other advantages including negligible vapour pressure, high intrinsic conductivity
without addition of supporting electrolyte and easy recyclability). In this frame, we will
present our recent extensive study aimed to the rationalization of the conducting film
features obtained in different conditions (i.e., RTILs vs non polar and polar VOCs, on
various electrode), both on model starting monomers (EDOT and EDOP) and on our
newly developed inherently chiral ones.
References:
[1] F. Endres, A.P. Abbott, D.R. MacFarlane, Electrodeposition from Ionic Liquids,
2008, Wiley-VCH, ISBN 978-3-527-31565-9.
[2] A.Pietrzyk, W.Kutner, R.Chitta, M. E. Zandler, F. D’Souza, F. Sannicolò, P.R.
Mussini, Anal. Chem., 2009, 81(24), 10061-10070.